1. Field of the Invention
The present invention relates generally to wireless networks, and more specifically to an ad hoc network in which mobile hosts are connected to each other via direct wireless links.
2. Description of the Related Art
An ad hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any centralized routing facility. Japanese Patent Laid-Open Specification Hei-8-37535 describes routing in an ad hoc network by having each mobile host maintain a routing table in which IP (network layer) addresses of destination hosts are mapped to IP addresses of transit hosts. When source and destination hosts are outside of the range of each other but within the range of a transit host, the latter acts as a router for routing packets between the source and destination hosts.
If mobile hosts were to use a number of wireless links to form an ad hoc network, these mediums would be identified by data link layer addresses in the routing table. Since the source host has no way of knowing which wireless link every other host is actually using, it will have to establish all wireless links and then broadcast a query packet to all destinations. However, this results in a low utilization efficiency of the network resource.
Another problem is that if mobile hosts having IP addresses of different network addresses were to form an ad hoc network, connections can only be established between mobile hosts of the same network address due to the lack of such routers and gateways of the type as used in wired backbone networks.